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<span style="mso-bidi-language:HI">Mossbauer, X-ray and magnetization studies of Ni<sub>0.5</sub>Zn<sub>0.5</sub>Al<sub>x</sub>Fe<sub>2-x</sub>O<sub>4</sub> system </span>http://nopr.niscair.res.in/handle/123456789/30641
Title: <span style="mso-bidi-language:HI">Mossbauer, X-ray and magnetization studies of Ni<sub>0.5</sub>Zn<sub>0.5</sub>Al<sub>x</sub>Fe<sub>2-x</sub>O<sub>4</sub> system </span>
<br/>
<br/>Authors: Suman; Lal, Roshan; Sharma, N D; Taneja, S P; Gupta, Ajay
<br/>
<br/>Abstract: <span style="mso-bidi-language:HI">The structural and magnetic properties of the
mixed spinel system Ni<sub>0.5</sub>Zn<sub>0.5</sub>Al<sub>x</sub>Fe<sub>2-x</sub>O<sub>4</sub>
(x=0.0, 0.2, 0.4, 0.6, 0.8 and 1.0) have been investigated by X-ray
diffraction, magnetization and Mossbauer measurements. The variation of
Mossbauer
<span style="mso-bidi-language:HI">parameters, lattice parameters and crystalline
size of the products formed with variation in the composition of Fe and Al ratio
has been studied. The studies confirm the formation of nano-size ferrite particles.
It is observed that lattice parameters
<span style="mso-bidi-language:HI">decrease, with increasing aluminium concentration.
A ferromagnetic relaxation occurs when <i>x </i>is increased to 0.6, which is followed
by weak paramagnetic transition. With further increase of <i>x </i>to 1.0 the
system again shows weak ferromagnetism. The decrease in magnetic hyperfine
field with increase in Al concentration has been explained on the basis of
super transferred hyperfine field. The variation of the saturation magnetic
moment per formula unit measured at 300 K decreases
<span style="mso-bidi-language:HI">with Al concentration <i>x, </i>suggesting the
decrease in ferromagnetic behaviour. These observations indicate the existence
of a non-collinear structure in a nano-particles ferrite system. The
non-collinear structure in this system is also verified by Neel's
<span style="mso-bidi-language:HI">two sub-lattice model.
</span></span></span></span></span>
<br/>
<br/>Page(s): 44-50Time dependence of Lippmann-Schwinger stateshttp://nopr.niscair.res.in/handle/123456789/8709
Title: Time dependence of Lippmann-Schwinger states
<br/>
<br/>Authors: Dubey, Ritesh Kumar; Menon, V J; Tripathi, D N
<br/>
<br/>Abstract: Due to the presence of an
infinitesimal parameter e in the resolvent, the Lippmann-Schwinger states cannot
be strict eigenstates of the Hamiltonian, and their time evolution is very
non-trivial (in agreement with Fermi’s golden rule). In sharp contrast, strict
Schrödinger eigenstates cannot make transitions into free channels. Artefacts
such as adiabatic switching, wave packets, or infinite time span are not needed
in our analysis.
<br/>
<br/>Page(s): 63-66Electronically tunable current-mode bandpass filterhttp://nopr.niscair.res.in/handle/123456789/8708
Title: Electronically tunable current-mode bandpass filter
<br/>
<br/>Authors: Shah, N A; Iqbal, S Z; Parveen, B
<br/>
<br/>Abstract: A new current-mode (CM)
operational transconductance amplifier-capacitor (OTA-C) structure implementing
second-order bandpass (BP) filtering response and offering a variety of
performances is presented. The use of one type of sources and grounded
capacitors (GC) considerably simplifies the implementation of the filter in
contemporary IC form. The electronic tuning of circuit characteristics has been
achieved orthogonally by adjusting the transconductance gain (gm) of OTAs. The
circuit possesses low sensitivity figures having values less than or equal to
unity lending it better performance feature.
<br/>
<br/>Page(s): 60-62Blue organic light emitting diode based on lithium tetra-(8-hydroxy-quinolinato) boron complexhttp://nopr.niscair.res.in/handle/123456789/8707
Title: Blue organic light emitting diode based on lithium tetra-(8-hydroxy-quinolinato) boron complex
<br/>
<br/>Authors: Kumar, Lokendra; Koireng, R R; Misra, Aparna; Kumar, Pankaj; Dhawan, S K; Kamalasanan, M N; Chandra, Subhas
<br/>
<br/>Abstract: Blue electro-luminescent materials are essential
for the development of full colour display. The synthesis and characterization
of blue emitter lithium tetra-(8-hydroxy-quinolinato) boron complex for organic
light emitting diode (OLED) applications have been reported. The boron complex
was synthesized by the reaction of lithium borohydride with 8-hydroxyquinoline
at room temperature and shows absorption cut-off wavelength at 410 nm and
bright blue photoluminescence (PL) with a peak wavelength at 485 nm. The
electro-luminescence (EL) and <i style="">I</i>-<i style="">V</i> characteristics of bilayer OLED are
also reported. The results show that boron complexes have a great potential for
the blue emitters for OLED applications.<b style=""></b>
<br/>
<br/>Page(s): 56-59